Binomial Nomenclature

Linnaeus a Swedish taxonomist proposed this theory of modern classification in 1758. He classified the living organisms as follows:

1. He gave two names to any species

2. First name is genetic or name of the genus and second name is specific or name of the species.

3. One genus and species name distinguishes the animal from other animals.

4. Both these names are Latinised form and is always written in italics or underlined in the manuscript.

5. First letter of generic name is always written in capital and that of species in small letter.

6. The generic and specific letter is written separately. e.g. common frog- Rana tigrina.

Trinomial Nomenclature

This nomenclature gave the name for sub-species. Some species due to their different habit and habitat showed certain minor changes. This causes the development of sub-species. To differentiate this subspecies, the third name was given to such different races. The sub-species name is written in small letter in handwritten manuscript and italicised in books. e.g. Indian and Pakistani crow-Corvus splendens. Burmese crow-Corvus splendens isolens and Crow of Ceylon-Corvus splendens protegatus.

It includes generic, specific and sub¬specific names. Thus it is known as trinomial nomenclature.